Motorcycles (and other two-wheeled, single tread vehicles) are very maneuverable and can be ridden at high speeds; however, these vehicles are inherently less stable than automobiles and other vehicles having more than two wheels. The speed and quick turning capability that motorcycles provide comprise a primary reason for the popular enjoyment of motorcycling; much of the allure of motorcycling is the freedom and “open individuality” that it bestows on the rider. The mechanical simplicity of the motorcycle form and the absolute responsibility of riders for safety and performance are additional attractions for riding.
Moreover, each motorcycle rider must balance the benefits of riding with the risks associated with the freedom and openness of the motorcycle. The Motorcycle Safety Foundation (MSF) teaches that motorcycling risks cannot be eliminated; however, they can and should be understood and managed in order to minimize such risks. The MSF uses the mantra, Scan, Identify, Predict, Decide and Execute (SIPDE) for each motorcycle rider to practice.
In riding a motorcycle, one of the most difficult aspects to learn is how to set the proper lean angle of the motorcycle to successfully navigate through a corner. A motorcycle must be leaned through an angle into the corner to balance the centrifugal force acting horizontally outwards on the motorcycle. At higher turning speeds the rider must increase the lean angle of the motorcycle into the corner in order to balance the increasing centrifugal force.
As used herein, the term “lean angle” is measured from the vertical position. A smaller lean angle is therefore closer to vertical and a greater lean angle is close to horizontal.
If the motorcycle's lean angle is too small (i.e. more vertical), the motorcycle will become unstable and topple over towards the outside of the corner. If the motorcycle's lean angle is too great (i.e. more horizontal), the motorcycle's tires will lose traction and the motorcycle will slide out from beneath the rider. It is of great importance that the rider learn the correct, safe lean angle for a corner; thus there is a need for an apparatus to control and set the lean angle for the rider.
Turning is the most difficult maneuver to control and execute when riding a motorcycle. A lack of confidence, education, training and experience can make turning more difficult and dangerous. Reports compiled regarding motorcycle accidents indicate that a high percentage of motorcycle accidents are single-vehicle accidents in which the motorcycle rider lost control and crashed without influence of another vehicle or obstacle. Many of these accidents occur while a motorcycle rider is attempting to navigate through a corner and tire traction is lost. Turning accidents can be caused by entering the corner too fast, exhibiting too much of a lean angle for the corner, locking the brakes, or a combination of these factors. Accidents can also happen when another traffic vehicle turns directly in front of an oncoming motorcycle causing the motorcycle rider to make an emergency turning and/or braking maneuver to avoid a collision. The possible outcomes of these accidents can include an off-road excursion, a collision, a “lowside” crash or a “highside” crash.
A “lowside crash” occurs as a result of one of two scenarios: 1) when the front and/or rear tire traction is lost due to too great of a lean angle in a corner, or 2) when the rear brake is “locked-up” in a corner, rear tire traction is lost thus swinging the rear of the motorcycle out of line towards the outside of the corner. In both of these scenarios the side of the motorcycle leaning into the corner slides down into the road surface, impolitely “dumping” the rider off of the “lowside” of the motorcycle and sliding the motorcycle.
A “highside” crash occurs as a result of one of three scenarios: 1) when the front brake is “locked-up” and held, 2) when the rear brake is “locked-up” in a corner, rear tire traction is lost thus swinging the rear of the motorcycle out of line and then the rear brake is suddenly released, and 3) when the rear tire traction is lost in a corner due to too great a lean angle, and the throttle is suddenly “rolled-off”. In the first scenario the front tire tucks in and under the motorcycle viciously throwing the rider up and over the “highside” of the motorcycle and “cartwheeling” the motorcycle. In the last two scenarios the sudden regain of rear tire traction results in a large reaction force that quickly “flips” the motorcycle up to the vertical and over, viciously throwing the rider up and over the “highside” of the motorcycle towards the outside of the corner and “body-rolling” the motorcycle.
To safely and successfully navigate through a corner the rider must employ the MSF mantra of Scan, Identify, Predict, Decide and Execute (SIPDE) so that the proper motorcycle speed and lean angle can be judged and set prior to the corner. Often though, for a motorcycle rider to avoid an accident, the rider must execute a tight turning maneuver very quickly. Such a turning maneuver is dependent upon the quickness of the steering initiative and the lean angle achieved by the motorcycle.
As previously noted, to achieve a left hand turning maneuver the rider must lean to the left or inside of the motorcycle. In order for the rider to get to the left side of the motorcycle, the rider must turn the motorcycle handlebars to the right. This is accomplished by the rider pushing out on (or pointing) the left handlebar. Because the handlebars are turned to the right to initiate a left turning maneuver, this process is referred to as “countersteering.” This rider input causes the rider to lean to the left, and as this happens the front wheel and motorcycle quickly and automatically turn to the left thus setting the turning radius based on the motorcycle lean angle. This process, though seeming counterintuitive, is best learned and remembered by the saying, “push (point) left, go left; push (point) right, go right”.
Thus the lean angle of the motorcycle as it enters and navigates through a corner is crucial to the tightness of the turning maneuver and whether the corner can be executed without an accident. The maximum lean angle is the maximum angle at which the motorcycle can lean from the vertical without the tires losing traction with the road surface. The maximum lean angle depends on the motorcycle speed, required turning radius, the centrifugal force/weight on each tire, tire material, (i.e., the material's coefficient of friction,) and the contour and coefficient of friction of the road surface. Generally, for safety reasons during normal turning maneuvers, a motorcycle rider will use a lean angle that is significantly less than the maximum lean angle; however, during emergency maneuvers, a tighter turning radius may be required. To achieve the tighter turning radius, the motorcycle rider must set a lean angle closer to the maximum lean angle, without exceeding it.
In professional motorcycle road racing conducted by definition on asphalt-paved circuits, the speed by which racers execute turning maneuvers is an important factor in determining the winner. On certain road race circuits, this factor is even more important than the horsepower of the motorcycle engine.
Motorcycle racers aggressively “countersteer” and lean far off the motorcycle seat into the corner, which is referred to as “hanging-off”. As noted previously, leaning into the corner helps counteract the centrifugal forces pushing the motorcycle to the outside of the corner. Because of the additional (racer) weight brought to bear on the inside of the motorcycle, “hanging-off” allows the motorcycle lean angle to be decreased and thus provide additional tire traction to navigate the same turning radius as a turning maneuver executed with the racer sitting in line with the lean angle of the motorcycle. The use of this additional tire traction allows the motorcycle to better navigate the tight corners without losing tire traction uncontrollably. “Hanging-off” also provides another advantage; racers can judge their lean angle throughout the turning maneuver by touching and feeling the asphalt with a pad attached to their knee. This enables racers to better repeat or gradually increase lean angles for certain corners they have become familiar with.
The best racers have on occasions used their padded knee to even help hold up and/or slightly push up the motorcycle to reduce the lean angle when they sense by experience that rear tire traction is about to be lost. This knee action and/or a carefully applied slight “roll-off” of the throttle reduce the motorcycle lean angle to maintain tire traction and prevent a “lowside” crash.
All dirt track motorcycle racers when turning on dirt tracks, will purposely initiate a severe “countersteering” input to the handlebars, to achieve extremely large motorcycle lean angles to deliberately lose rear tire traction and slide the rear motorcycle tire towards the outside of the corner. This maneuver turns the motorcycle to a direction pointing out of the corner more quickly, widens the track of the motorcycle through the corner and allows a racer to “roll-on” the throttle quicker, i.e., move into and out of the corner more quickly. Racers on dirt tracks “plant” the heel of their inside foot outwards and into the loose dirt as a stabilizing, weighted support member while they wrestle the motorcycle to the extreme maximum lean angle. This technique is referred to as “squaring-off” the corner. This exact technique cannot be used on asphalt (road race) surfaces with motorcycles because of the hazard of a “lowside” or “highside” crash and the danger of using one's foot as a weighted support member on hard asphalt.
The best professional road racers who have experience dirt track racing do occasionally attempt to accomplish some “squaring-off” of a corner on asphalt by purposely “rolling-on” or applying more throttle to “break” or lose rear tire traction. This is referred to as “throttlesteering” because the throttle is employed to slide out the rear tire to help steer the motorcycle rather than only relying on only “countersteering” and lean angle. This is accomplished without the placement of the foot or knee on the asphalt for weighted support. “Throttlesteering” realizes some of the benefits associated with “squaring-off”, but it creates a much more dangerous scenario. Once the motorcycle begins sliding it becomes basically uncontrollable and liable to crash. The crash will be a “lowside” crash if too much throttle “roll-on” is applied and too great a lean angle results; or the crash will be a “highside” crash if traction is regained too quickly by means of braking or “rolling-off” of the throttle.
In order to regain traction and prevent a “lowside” crash without causing a more horrific “highside” crash, the racer must execute immediate, almost instinctive, maneuvers such as body repositioning and/or a carefully applied slight “roll-off” of the throttle. Often, if lucky, the racer may regain both traction and control after only an upsetting “wiggle & shake” of the motorcycle. This “wiggle & shake” is the beginning of the “highside” action, and may pitch the racer up from the seat and foot pegs and causes the motorcycle to divert from the path along which it had been traveling.
In any case, controlling a motorcycle to successfully regain rear tire traction while executing a turning maneuver is one of the most difficult challenges either on the racetrack or the street. The description of this present invention will include discussions regarding apparatus and method for prevention and solution of this matter.